Is there a woman alive who has not in some way, directly or indirectly, been touched by anorexia nervosa? My own first encounter with the hungry hell was as a 16-year-old. I was invited home by a schoolfriend who refused to sit at the table for excruciatingly formal meals. At night, she would make me hold the torch as she rummaged through the dustbin to retrieve the cartons that had held her little brother's ice-cream. She could lick, but she wouldn't eat.

"Anorexia," as Kate Chisholm rightly notes, "is a crippling, antisocial disease that cuts you off from your real self and everyone you know and love." It is "a retreat into aggressive isolation".

Chisholm was 24 when what she had scrupled to call an illness landed her in hospital for the first time. It was 1977. The system at the Westminster hospital, where she was "treated", was - staggeringly - geared to increase food intake to 5,000 calories a day in the space of a fortnight, by pretty much force-feeding patients all the foods they most feared six times a day. To help it go down they were drugged, in a regime that sounds more like a foie gras factory than therapeutic practice.

Twenty years later, she is relieved to note, the consultant who devised the Westminster regime had changed his views. Drugs were no longer used and neither was coercion. Revealingly he went on to note that "the inpatient's refusal to eat can arouse considerable anger and aggression in doctors and nurses".

The apparent self-destruction of perfectly healthy girls - and anorexia is predominantly, though not exclusively, a female condition - is a mystery that has attracted many different sorts of theorist. One of the points Chisholm is keenest to make - so keen that it becomes a repeated refrain - is that anorexia is not a recent phenomenon and cannot therefore be glibly blamed on fashion or advertising. "It has always been present, and the way it presents is always the same." She backs this up with a wide range of references - from recent cultural theorists and memoirists right back to 17th-century reports on the "Derbyshire Damosells", a group of women whose fasting put them at the centre of a debate as to whether they were blessed (as their local priest believed) or manifestly sick (as the philosopher Thomas Hobbes argued).

All of which prompts the question: if anorexia has been around for so long, why are we so bad at dealing with it - especially since, as Chisholm asserts, it kills more people than any other psychiatric condition and can be expected to cause the deaths of 20% of those who suffer from it?

Perhaps a clue lies in that consultant's observation about the anger that the anorexic can inspire in even the people trained to deal with them: if doctors and nurses get cross, then what of the wider society from which the anorexic comes and to which he or she will, hopefully, return? Chisholm acknowledges, in retrospect, her parents' desperation - but one of the interesting disjunctions of the book is that she has no memory of being aware of it at the time. Her diary blandly reports a "showdown with Ma and Pa"; she also remembers a row between her father and the hospital, but only later does she realise what it was about. He had objected to what he felt was an inhumane regime - but the self-centredness of the patient meant that his feelings were out of the picture.

The problem with this gulf between the healthy and un-healthy mind is that Chisholm can report, but is hard-put to re-imagine, how she felt. The weakest parts of the book are the little scenarios enacting anorexic arguments for not eating. Here, you feel, she is struggling to articulate something she is too honest to reinvent but can no longer, in the deepest sense, understand. Luckily for her.